Inflatable mattresses



1969 J. H. s. SCOTT T AL 3,426,373

INFLATABLE MATTRESSES Filed Oct. 1'7, 1966 United States Patent 3,426,373 INFLATABLE MATTRESSES James H. S. Scott, 35 Mansionhouse Road, and Wilfred Salisbury, 17 Marchmont Crescent, Edinburgh 9, Scotland Filed Oct. 17, 1966, Ser. No. 590,165 Claims priority, application Great Britain, Oct. 18, 1965,

44,104/ 65 US. Cl. -348 4 Claims Int. Cl. A47c 27/08 ABSTRACT OF THE DISCLOSURE The present invention relates to an inflatable undermattress for medical and surgical use. The object of the invention is to provide an under-mattress which can be used to vary the position of a bed-ridden patient, so changing the pressure points on the patient, without the patient being handled by nursing staff.

According to the invention an inflatable undermattress comprises a base member having at each side thereof an inflatable chamber, each chamber being so shaped that when inflated the upper surface thereof is inclined downwardly towards the centre of the mattress.

It will be appreciated that by inflating one or other of the chambers a patient supported by the mattress can be moved or tilted to one side or the other. Apart from changing the pressure points on the patient regular movement of this sort assists to maintain circulation and also adds greatly to the general comfort of the patient. The presence of the under-mattress beneath an ordinary mattress causes no discomfort to the patient.

Preferably each inflation chamber is formed between the base member and a sheet of material positioned above the base member and joined thereto along free edges. Alternatively each chamber may be formed by a separate bladder enclosed in a pocket of which the base member forms part.

The chambers can be of any required shape and size. Preferably they extend the full length of the mattress and have one side defined by a side of the mattress and the other side curved to increase the width of the chamber from the foot end to the head end of the under-mattress, the curved edges of the two chambers converging towards, and preferably meeting at, the head end of the mattress.

This shaping creates a central hollow along the undermattress, wide at the foot end thereof, and narrowing toward the head end thereof. This helps prevent the patient being rolled out of bed on inflation of the chambers.

An under-mattress according to the invention will now be described in more detail, by way of example, with reference to the accompanying drawings in which:

FIGURE 1 is a plan view of the under-mattress;

FIGURE 2 is a section on the line IIII of FIGURE 1, with the under-mattress in an inflated condition; and

FIGURE 3 is an electrical and pneumatic circuit diagram of central apparatus for the under-mattress.

The under-mattress is built up of pieces of rubbercoated fabric, assembled in an unvulcanised condition, and then vulcanised. The mattress comprises a base member 1,

3,426,373 Patented Feb. 11, 1969 and two inflatable chambers 2 and 3 on opposite sides of the base member. The two chambers are identical in shape and construction and only the chamber 2 will be described in detail.

The chamber 2 is defined by a part of the base member 1, a rectangular side wall 4, triangular end walls 5 and 6 and an upper wall 7. The side wall 4 and base member I are joined together by a strip 8 of rubber-coated fabric, the side and upper walls 4 and 7 are joined by a similar strip 9, and the end wall 5 is joined to side wall 4, upper wall 7 and base member 1 respectively by strips 10, 11 and 12. The end wall 6 is similarly joined to the base 1, side wall 4 and upper wall 7. The corners of the mattresses have circular patches 2-1 applied thereto to hold them and make them airtight. The inner edges 13 and 14 of the chambers 2 and 3 respectively are curved, and converge towards the head end of the mattress. These edges are secured to the base member 1 by means of an extruded rubber section 15 and 16 respectively. Patches 22 are applied at the end of the sections 15 to ensure an airtight joint.

An inflation tube 17 is fitted into the sidewall 4, and a similar tube 18 fits into the side wall of the other chamber 3. The tube 17 has a rosette end 19 secured to the inner side of the wall 4, and is also secured to the outer side of this wall by a ring patch 20. Each of the inflation tubes 17 and 18 can be connected to a compressed air supply as will be described later.

The mattress as described is assembled by joining together the base, and the side, upper and end walls while laid flat, the joint being achieved by freshening the surfaces of these members and the surface of the joining strips, and rolling down and stitching the joints. Tacky rubber surfaces are dusted off as the work proceeds to avoid any accidental adhesion. The inflation tubes are fitted into the side walls. When the mattress is assembled in the flat the upper walls are folded over and joined to the end walls and the end edges of the side walls. The inner edge of each upper wall is then secured to the .respective extruded section 15 or 16 which is fixed to the base. The corner patches 21 and patches 22 are then applied, and the complete mattress is then vulcanised.

The area of the mattress is such that a person of any weight can readily be moved by a pressure of 1 lb. per square inch above atmospheric pressure, a pressure that can be achieved by the blowing end of a small vacuum cleaner connected to the inflation tube of the chamber. A simple stop or valve can be incorporated in the inflation tube so that after a period of time air can be released from the inflated chamber and the patient tilted in the opposite direction by inflating the other chamber. If desired, a simple regulation valve may be included which permits an inflated chamber to deflate gradually over a given period of time.

In cases where frequent examination of the patient by nursing staff is not required, the inflation chambers can be controlled to permit automatic inflation and deflation. Such a control unit will now be described with reference to FIGURE 3.

As shown in FIGURE 3 a pneumatic circuit comprises four air compressors for feeding into a common manifold M. Outlet through the manifold is by way of two solenoidcontrolled valves SV1 and SV2 controlling air supply to and from lines 23 and 24 respectively. Line 23 is connected to the inflation tubes 17 and 18. The valves SV1 and SV2 are two position valves connecting the tubes 23 and 24 either to the manifold M or to exhaust by way of regulator valves RV1 and RV2 respectively. Electrical connections to the one side of the solenoids of the valves SV1 and SV2 are made by way of a timer T to one side on an electrical input. This side of the input is also connected to the compressors C by way of the selector switch SS, and the input is made through a master switch 25.

In operation the master switch is closed and the selector switch is moved to select the required number of compressors to give the pressure required. For a heavier patient more compressors will be switched in than will be needed for a lighter patient. The timing unit T operates first to energise the solenoid of valve SV1 so connecting the line 23 to the manifold M as indicated by the solid line position of this valve. Air is thus pumped through the compressors from the manifold and valve SV1 into the chamber 2 to inflate this. During this time the solenoid of valve SV2 is not energised so that inflation chamber 3 is connected through line 24 and the valve SV2 to the regulator valve RV2 and thence to atmosphere as indicated by the solid position of valve SV2. After a predetermined interval the solenoid valve SV1 is de-energised to that the inflation chamber 2 is connected to the regulator valve RVl. The chamber 2 then deflates gradually over a period of time depending on the setting of the valve RV1. When the chamber 2 is deflated the timer makes a circuit to energise the valve of SV2 so that the chamber 3 is connected to the compressors and is thus inflated. Subsequently the solenoid of valve SV2 is de-energised and the chamber 3 connected to regulator valve RV2 to deflate gradually as required. This cycle is repeated and it will be seen that a patient is thus moved gradually through a few degrees from side to side at regular intervals so that the pressure points on the body are changed and the patients circulation is assisted.

It will readily be appreciated that the electrical and pneumatic circuits of the control unit can be subjected to considerable variation to give whatever result is required by the nursing staff. Furthermore, rather than have the walls to the inflatable chambers 2 and 3 formed directly by the walls of the mattress the chambers may be defined by separate inflatable bladders enclosed in pockets of the mattress. The shape of the individual chambers is not limited to that shown in the drawings, although this shape is particularly desirable in that the central hollow prevents the patient from being rolled out of bed on inflation of the chambers. Furthermore it means that only the torso of the patient is moved on inflation of the chambers and the lower part of the body tends to remain stationary so aiding to stabilise the patients position.

We claim:

1. An inflatable under-mattress comprising a base member having at each longitudinal side thereof an inflatable chamber, said chambers being independently inflatable, each of said chambers being so shaped that when inflated the upper surface thereof is inclined downwardly towards the center of the under-mattress and each of said chambers having one longitudinal side extending along the length of the under-mattress along one side thereof, and the other side of each of said chambers being so shaped as to increase the width of each of said chambers from the foot end to the head end of the under-mattress, whereby the upper body portion of a person is moved upon inflation of said chambers while the lower body portion tends to remain stationary.

2. An inflatable under-mattress according to claim 1 in which each of said inflation chambers is formed between said base member and a sheet of material positioned above said base member and connected thereto by way of free edges. W

3. An inflatable under-mattress according to claim 1 in which each of said chambers extends the full length of the under-mattress, and has said one side defined by said one side of the under-mattress and has said other side curved to increase the width of each of said chambers from the foot end to the head end of the under-mattress.

4. An inflatable under-mattress according to claim 1 in which means are provided for inflating said chambers alternately at regular intervals and for allowing said chambers to deflate gradually.

References Cited UNITED STATES PATENTS 1,772,310 8/1930 Hart 5348 XR 3,276,047 10/ 1966 Emery 5349 3,303,518 2/1967 Ingram 5349 FOREIGN PATENTS 811,378 8/1951 Germany. 629,620 3/ 1963 France.

BOBBY R. GAY, Primary Examiner.

A. CALVERT, Assistant Examiner. 

